Why are some Asian populations more prone to hypercholesterolemia?

Why Some Asian Populations Are More Likely to Have High Cholesterol

South Asian populations in particular have a distinct dyslipidemia pattern that contributes to their increased risk of atherosclerotic cardiovascular disease (ASCVD). The typical lipoprotein pattern in South Asians is characterized by hypertriglyceridemia, low levels of HDL cholesterol, and qualitatively abnormal LDL particles that are smaller and denser, even when LDL cholesterol levels may not appear elevated. 1

Genetic and Environmental Factors

Genetic Predisposition

• South Asians have genetic variants that affect lipid metabolism, particularly:
  • Higher lipoprotein(a) [Lp(a)] levels, especially in South Asian women compared to European women 1
  • Plasma Lp(a) levels are highly genetically controlled (>90% of variability explained by genetic variants) 1
  • Higher apolipoprotein B100 to apolipoprotein AI ratio, which predicts atherogenesis 1

Environmental Influences

• Migration studies show dramatic changes in cholesterol levels when Asians adopt Western lifestyles:
  • Chinese immigrants in New York's Chinatown had significantly higher total cholesterol than those living in Shanghai (206 mg/dL vs. 160 mg/dL for males ≤30 years) 2
  • Japanese immigrants in Hawaii and San Francisco had higher plasma cholesterol and CHD incidence than those in Japan 1

Body Composition and Metabolic Factors

• South Asians develop metabolic syndrome at lower waist circumference than whites 1
• Increased visceral adiposity contributes to insulin resistance 1, 3
• Diabetes develops at lower body mass and earlier ages in South Asians 1
• Insulin resistance serves as a common interface between body composition and dyslipidemia in Asian Indians 3

Dietary and Lifestyle Influences

• Traditional Asian diets (like Japanese and Okinawan) were historically very low in fat:

  • Traditional Okinawan diet in 1949: only 6% of calories from fat (compared to 8% in other Japanese areas) 1
  • The shift from traditional diets to Western diets high in total fat and processed foods has contributed to rising cholesterol levels 1, 4

• Physical activity differences are significant:

  • Studies comparing Bai Ku Yao and Han Chinese populations showed that higher physical activity levels were associated with better lipid profiles 4
  • Urbanization has had a negative impact on cardiovascular risk factors in South Asians 1

Clinical Implications

• South Asians may respond differently to statin therapy:

  • Japanese patients may be more sensitive to statin dosing, requiring lower doses for similar efficacy 1
  • The Pooled Cohort Equations (PCE) for ASCVD risk may underestimate risk in South Asians and overestimate risk in East Asians 1

• Coronary artery calcium (CAC) scores vary by ethnicity:

  • South Asian men have CAC burden similar to non-Hispanic white men but higher than blacks, Latinos, and Chinese Americans 1
  • South Asian women have CAC scores similar to whites and other racial/ethnic women 1

Prevention and Management Approaches

• Lifestyle modifications should be culturally tailored:

  • Dietary recommendations should consider ethnic food preferences 1
  • Physical activity interventions should be culturally relevant 1
  • Technology-based interventions (web tools, mobile messaging) have shown success in South Asian populations 1

• Lipid management should follow general guidelines but with ethnic considerations:

  • LDL-C goals of <100 mg/dL for high-risk patients and <70 mg/dL for very high-risk patients 1
  • Address the atherogenic dyslipidemia pattern (high triglycerides, low HDL, small dense LDL) common in South Asians 3

Conclusion

The higher prevalence of dyslipidemia in certain Asian populations, particularly South Asians, results from a complex interplay of genetic predisposition, body composition differences, metabolic factors, and environmental influences including diet and physical activity. Understanding these population-specific differences is crucial for developing targeted prevention and treatment strategies to reduce cardiovascular disease burden.